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Diffstat (limited to 'arch/sparc/kernel/signal_32.c')
-rw-r--r--arch/sparc/kernel/signal_32.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 8ce247ac04c..d54c6e53aba 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -519,10 +519,26 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
519 siginfo_t info; 519 siginfo_t info;
520 int signr; 520 int signr;
521 521
522 /* It's a lot of work and synchronization to add a new ptrace
523 * register for GDB to save and restore in order to get
524 * orig_i0 correct for syscall restarts when debugging.
525 *
526 * Although it should be the case that most of the global
527 * registers are volatile across a system call, glibc already
528 * depends upon that fact that we preserve them. So we can't
529 * just use any global register to save away the orig_i0 value.
530 *
531 * In particular %g2, %g3, %g4, and %g5 are all assumed to be
532 * preserved across a system call trap by various pieces of
533 * code in glibc.
534 *
535 * %g7 is used as the "thread register". %g6 is not used in
536 * any fixed manner. %g6 is used as a scratch register and
537 * a compiler temporary, but it's value is never used across
538 * a system call. Therefore %g6 is usable for orig_i0 storage.
539 */
522 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) 540 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
523 restart_syscall = 1; 541 regs->u_regs[UREG_G6] = orig_i0;
524 else
525 restart_syscall = 0;
526 542
527 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 543 if (test_thread_flag(TIF_RESTORE_SIGMASK))
528 oldset = &current->saved_sigmask; 544 oldset = &current->saved_sigmask;
@@ -535,8 +551,12 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
535 * the software "in syscall" bit, directing us to not perform 551 * the software "in syscall" bit, directing us to not perform
536 * a syscall restart. 552 * a syscall restart.
537 */ 553 */
538 if (restart_syscall && !pt_regs_is_syscall(regs)) 554 restart_syscall = 0;
539 restart_syscall = 0; 555 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) {
556 restart_syscall = 1;
557 orig_i0 = regs->u_regs[UREG_G6];
558 }
559
540 560
541 if (signr > 0) { 561 if (signr > 0) {
542 if (restart_syscall) 562 if (restart_syscall)